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Wind Power. Approximately 2% of the solar power that reaches the earth’s surface is converted into wind. This is ~30 times our present energy usage. History. Large sailing ships could generate 10 000 hp. Used extensively in Europe in the 19 th century
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Approximately 2% of the solar power that reaches the earth’s surface is converted into wind. • This is ~30 times our present energy usage.
History • Large sailing ships could generate 10 000 hp. • Used extensively in Europe in the 19th century • Used for pumping water or grinding grain • Most rapid new development for generating electricity
Early wind generators focused on single large generators • Grandpa’s Knob (Vermont) could generate up to 1.2 MW of power in the 1940’s. • 200 ft diameter blades
New interest in wind electricity after oil embargo in 1973. • Early NASA wind generator built in Ohio in 1975 could generate 100 kW of power in 18 mph wind using 125 ft long blade diameter.
Boeing Mod 5B wind turbine on Oahu designed to generate 7.2 MW of electricity. Actually, produced 3.2 MW operating from 1987 - 1993 • 420 ft diameter on a 192 ft tall tower • Last government-sponsored project.
Many Different Styles Darius Rotor Savonius Rotor 2-Blade Wind Turbine 3-Blade Wind Turbine American multivane
Choice of style depends on application • Multi-blade has good starting torque. Good for applications like pumps. • 3-blade has low starting torque but is more efficient at high rotation rates. Used for generating electricity
Wind Farms • Rather than using single large generator, we usually use several smaller generators to make wind farms
Practicalities • Wind speed tends to increase with increasing height. Optimal height is ~300 m. • Most commercial wind towers are 50 to 100 m high. Get ~80% of wind potential at this height.
Power in the wind(Betz Limit) P=2.8310-4 D2v3 kW D is the diameter in meters v is the wind speed in meters per second D2 - because area of windmill increases as D2 v3 - because KE in wind is proportional to v2 and an additional v because of rate at which energy is brought to windmill
Maximum theoretical efficiency is 59% of the Betz limit. • Modern wind generators are around 50-70% of maximum theoretical efficiency
You want to place wind generators in a location that get consistently high wind power.
Rated Output • A wind generator has a rated power output a a particular wind speed, e.g. 10 kW at 20 mph. • If wind speed drops so does power, e.g. if wind drops to 15 mph, P=(15/20)3 10kW = 4.2 kW. • If wind speed increases, they usually feather the blades so they don’t generate too much power.
Home Wind Power? • HORNET - LOW WIND SPEED turbines with Split-Core PMA • Hornet's are designed for class 3 to 7or AVERAGE wind zones. • Super low cost turbines! • 59" diameter blade • 800 Watts @ 33 MPH • 1200 Watts MAX. @ 65 MPH (under load) • ~$500.00 • Note at 11mph P=800/27=30W
Globally averaged growth in wind power has been 34% for the last five years. • Goal: Have wind provide 5-10% of our electricity by 2020. (Currently it is ~2.3 %) Fall 2011: 43.5 GW installed (90 projects for another 8.5 GW under construction) • The EU was attempting to provide 20% by 2010. As of 2010, 84 GW (12 000 turbines), which is 9.1 %.
Illinois Energy Context • Electric Profile (2009) Data from the Energy Information Administration
Advantages • Renewable • No CO2 or other emissions • Competitive price per kW-h • Less than 1% of the land would be used for foundations and access roads, the other 99% could still be used for farming or other uses.
Advantages Diversify the predominantly coal and nuclear energy profile in Illinois and provide a hedge against rising energy costs Every megawatt of installed wind capacity generates $1.7 million of investment Renewable energy projects such as wind development contribute significantly to the local tax base Each wind turbine can provide $2,000-$4,000 per year in lease payments thereby diversifying the income of farmers, ranchers and other landowners
Concerns About Wind Power • Wind is intermittent so you don’t want to rely on it too much. ~15-20% is considered safe. • Aesthetics: Actually more opposed to by people who don’t live near them. • Noise: New designs are very quiet
Concerns About Wind Power • Bats & Birds • 30 % of first year bird deaths are due to collisions in nature • interactions with humans and human-made objects cause many bird deaths